Even though no specific rule bans touching in public, it’s more of a “precedent” set by the Queen for the rest of the family to follow.

He said: “The Queen rarely holds hands with her husband in public and this seems to have set an unwritten precedent for the other royals.

“It is very clear that William and Kate are emotionally close, however, they do not seem to feel the need to prove their love – particularly when on official state business.”

Harry and Meghan aren’t the only royal couple to flout this unspoken rule.

Royal etiquette expert Myka Meier told PEOPLE that it all comes down to personal preference.

She said: “We often see Prince Charles and The Duchess of Cornwall holding hands – it’s all simply a matter of preference for each couple and is also likely dependent on the nature of the event they are attending.

“A more serious engagement would warrant a more serious level of professionalism, which each royal is sure to follow.”

Previously, onlookers were excited to spot Meghan looking loved up at Ascot.

The Duchess of Sussex was even seen holding Camilla Parker Bowles’ hand at Prince Charles’ 70th birthday celebrations.

The Suits star actress was offered advice from the Princess of Greece this week after the rule breaks.

She will next appear with Harry at the Your Commonwealth" Youth Challenge Reception on July 5.